1. Field of the Invention
This invention relates to a driving system for a self-shift type gas discharge panel for multi-row display, and specifically to a new driving system which allows shift operation of a selected row independently of other non-selected rows.
2. Description of the Prior Art
A self-shift type gas discharge panel providing a discharge spot shifting function has been developed for simplifying the driving circuit of the matrix display AC driven gas discharge panel, and is basically composed of shift channels defined by a regular arrangement of a plurality of discharge cells. Various kinds of such panels have been proposed. For example, the U.S. Pat. No. 3,944,875 by Owaki et al assigned to the assignee of the present invention discloses a typical self-shift panel providing the matrix electrode structure. In addition, the U.S. Patent Applications Ser. No. 813,627 and No. 810,747 by Yoshikawa et al, also assigned to the assignee of the present invention, both disclose an improved type of self-shift panel providing a meander electrode arrangement and a meander channel structure.
In order to attain multi-row display in this type of self-shift gas discharge panel, independent shift operation is required for each row. Namely, while writing is newly performed or rewriting is executed in the selected shift row, data in the remaining non-selected shift row must be held at a specified position.
A general method of such selective shift operation for multi-row display is described, for example, in "Self-Shift Character Display" in the FUJITSU Scientific and Technical Journal, Vol. 11, No. 2. pp. 81-98, June 1975. According to this disclosure, in the existing method, each Y electrode group defining each shift row of a panel of the matrix electrode structure is individually led out, and a shift voltage is applied to the Y electrodes of the non-selected row at a certain phase timing for holding the existing data. This method has the disadvantage that a difference is generated between the operation margins of the selected and non-selected shift rows, since the discharge mode in the panel is different in the selective shift operation from in the discharge mode of the non-selective holding or display operation in the other shift rows. This results in various problems, such as data being destroyed, or mis-firing occurring at the time of transfering between these two operations. Also a difference in the brightness of the discharge spots results in transfering between the selective shift operation and the display operation, which may be unpleasant to the operator viewing the display.